Antônio Frederico de Castro Alves (March 14, 1847 – July 6, 1871) was a Brazilian poet and playwright, famous for his abolitionist and republican poems. One of the most famous poets of the "Condorism", he won the epithet of "O Poeta dos Escravos" ("The Poet of the Slaves").

In 1867, Alves returns to Bahia alongside Câmara, and there he writes his drama Gonzaga, ou A Revolução de Minas, based on the life of famous Luso-BrazilianNeoclassic poet Tomás António Gonzaga and his participation in the failed 1789 Minas Conspiracy. In the following year, he and Câmara would go to São Paulo, where Alves entered the Faculdade de Direito da Universidade de São Paulo and once more would meet Ruy Barbosa. In there, he also befriended Pedro Luís Pereira de Sousa, and wrote a poem named "Deusa incruenta", based on Sousa's work "Terribilis Dea". His play Gonzaga would be performed on the end of 1868, being well received by critics and public alike, but Alves was sad because his romantic engagement with Eugênia Câmara had terminated.

During a hunting trip in the same year, Alves received an accidental shotgun shot in his left foot, that had to be amputated due to the menace of gangrene. However, a prosthesis was made for him, and thus he was able to walk again (although with the use of an assistive cane). He would spend the year of 1870 in his home-state of Bahia, trying to recover from the tuberculosis he got while in São Paulo. Also in 1870, Alves published the poetry book Espumas Flutuantes — the only work he would publish during his lifetime. All his other works would receive a posthumous publication.

Alves' attempts to mitigate the tuberculosis were in vain; he would die on 6 July 1871, in the city of Salvador, at 24 years old.